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Dentistry: Guide to New Dental Amalgam Rule


For questions or more information, please email DentalAmalgam@

Send compliance forms by email to DentalAmalgam@

or by mail to:

Bureau of Environmental Services
Water Pollution Control Lab
Attn: Dental Amalgam
6543 N. Burlington Avenue
Portland, OR 97203-5452

Effective July 15th, 2017 the Federal Environmental Protection Agency (EPA) announced new effluent guidelines for dental practices that discharge wastewater associated with the placement or removal of mercury containing amalgam (40 CFR Part 441).  Dental practices that place or remove mercury-containing amalgam, in or from patients, must submit a periodic certification to the control authority verifying that specific Best Management Practices (BMPs) are being followed.  The federally mandated BMPs necessitate the installation, operation, and maintenance of best available technology, amalgam separators, to reduce the discharge of mercury-containing solids to the City of Portland’s (City) Publicly-Owned Treatment Works (POTW).  The City has been delegated authority from the state of Oregon’s Department of Environmental Quality (DEQ) to ensure that the dental practices who discharge to the City of Portland comply with the required Best Management Practices. If your facility discharges to the City of Portland’s sanitary sewer, your control authority and reporting responsibility is to the City of Portland. Facilities located in the following surrounding districts have contributing agreements to send a portion of their sewer to City of Portland: Clackamas, Gresham, Dunthrope-Riverdale, Lake Oswego, Milwaukie, Tualatin, Hillsboro, and West Hills Service District. If your dental facility is in a contributing jurisdictions and you receive a notice, your location has been identified by a sewer mapping database as a discharger to the City of Portland. These facilities will be required to submit annual compliance certification materials to the City of Portland only. The City’s annual reporting requirements are more stringent than the federal EPA requirement of a one-time compliance report unless your facility is exempt from the rule. The City of Portland will send reminders and/or certification documents annually to your facility if your dental practice is subject to the rule.


Dental amalgam — typically referred to as a “silver filling" — is made of two nearly equal parts; liquid mercury, and a powder containing a mixture of silver, tin, copper, zinc, and other metals. The pollutant of concern in this alloy is the heavy metal mercury, which can have a bioaccumulative toxic effect that persists when introduced into the environment, especially in aquatic ecosystems. Amalgam discharged to City of Portland wastewater treatment facilities has the potential to enter local waterways through discharge to the Willamette and Columbia Rivers. Controlling amalgam discharges benefits the health of our local ecosystems.

Who is Affected by this Rule?

This rule applies to offices, including large dental institutions and clinics, where dentistry is practiced who discharge to City wastewater treatment facilities. Facilities who are affected by this rule will be required to submit compliance certifications annually by January 15th.


New facilities that begin discharging to a publicly owned treatment plant on or after the effective date of July 15, 2017 are expected to comply immediately. Within 30 days of opening, these businesses must submit a signed Compliance Certification and include proof of installation of an amalgam separator that removes 95% of solids in accordance with ISO 11143 at the new facility to: If emailing a signed scanned document, keep the original onsite. Keep any maintenance logs, and records of amalgam waste disposal from a period of up to three years. The City of Portland may conduct a site inspections to verify compliance with the rule. New sources will then be required to submit Compliance Certification and accompanying documentation each following year. Change in ownership at a facility is considered a new source and the new owner must submit the Compliance Certification within 30 days. 


Facilities in business before the effective date of July 15, 2017, are expected to be in compliance under the 2007 State of Oregon Senate Bill 704-B. Existing facilities will have three years from the effective date to retrofit their offices with the required equipment. Existing facilities will be required to submit Compliance Certifications and supporting documentation. Supporting documentation refers to the Best Management Practices (BMPs) listed on the Compliance Certification (i.e. proof of maintenance and/or off-site disposal).

Who is Exempt from this Rule?

This rule does not apply to mobile units or offices where the practice of dentistry consists only of the following dental specialties: oral pathology, oral and maxillofacial radiology, oral and maxillofacial surgery, orthodontics, periodontics, or prosthodontics. Also excluded are dental offices that do not place or remove amalgam except in limited, emergency or unplanned, unanticipated circumstances. However, these types of facilities will need to submit a one-time Compliance Certification and complete the waiver request section on the form.

Rule Requirements


Compliance Certification

Equipment & Amalgam Waste Management Log

Oregon requires dental offices to meet most of the requirements of this new rule under State of Oregon Senate Bill 704-B. BMPs to be followed by all facilities affected by the rule include:

  • Treat all amalgam wastewater through properly-sized amalgam separator(s), certified to remove at least 95% of total amalgam solids, in accordance with ISO 11143.
  • Inspect the amalgam separator(s), at a minimum, once per month to ensure proper operation and confirm that there is no bypass of the treatment system (441.30(a)(2)(v)).
  • Repair or replace defective amalgam removal equipment/components in accordance to the manufacturer’s instructions (441.30(a)(2)(vi)).
  • Regularly maintain the amalgam separator(s) by replacing retaining cartridges, separator canisters, filters, and/or other treatment units annually, or whenever the unit reaches the manufacturer’s design capacity, whichever comes first.
  • The use of oxidizing or acidic cleaners to flush dental unit water lines is prohibited.
  • Collect scrap amalgam from chair-side traps, screens, vacuum pump filters, dental tools, and/or other collection devices for off-site disposal. Scrap amalgam must not be flushed down the drain (441.30(b)(1-2)).

All dental facilities are required to fill out an initial compliance report (Dental Discharger Certification) following the directions outlined in the form. Facilities exempt from rule § 441.10 are required to fill out the form once and request a waiver (section F) for exemption from future certification requirements. Discharging dental facilities subject to the rule are required to submit a completed Discharger Certification and official documentation from the final point of recycling for your most recent recycling date of amalgam canister and/or amalgam bucket/containers. Contact your recycling service or amalgam separator servicer if needed and ask for documentation. Subsequent annual certifications will require a copy of your facility’s Equipment & Amalgam Waste Management Log in addition to a completed Dental Discharger Certification.

Record Retention

Compliance Certification: The dental facility or an agent or representative of the dental facility must maintain this Compliance Report and make it available for inspection in either physical or electronic form.

Other Records: The Dental facility subject to this rule must maintain documents and make available for inspection in either physical or electronic form for a minimum of three years, including receipts and manifests.

  • Documents related to inspection of amalgam separators and follow-up actions.
  • Documentation of amalgam retaining container or replacement, including date, if applicable.
  • Documents related to dental amalgam pickup or shipment for proper disposal by a licensed storage or disposal facility.
  • Documentation of any repair or replacement of an amalgam separator or device.
  • Manufacturer’s current operating manual for the device in place.

Program Fees

There is no program fee associated with your facility's first compliance report submission. However, facilities affected by this rule who are required to submit an annual compliance certification the following years will be subject to an annual fee of $100 to be billed separately.